Product Specifications for Recombinant Human Siglec-3/CD33 His-tag Protein, CF
Chinese Hamster Ovary cell line, CHO-derived human Siglec-3/CD33 protein Met17-His259, with a C-terminal 6-His tag
>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
<0.10 EU per 1 μg of the protein by the LAL method.
N-terminal sequence Analysis
Predicted Molecular Mass
44-49 kDa, under reducing conditions
Measured by the ability of the immobilized protein to support the adhesion of human red blood cells.
The ED50 for this effect is 0.1-0.8 µg/mL.
Scientific Data Examples for Recombinant Human Siglec-3/CD33 His-tag Protein, CF
Recombinant Human Siglec-3/CD33 His-tag Protein Bioactivity
Recombinant Human Siglec-3/CD33 His-tag (Catalog # 10375-SL) supports the adhesion of human red blood cells. The ED50 for this effect is 0.1-0.8 μg/mL.
Recombinant Human Siglec-3/CD33 His-tag Protein SDS-PAGE
2 μg/lane of Recombinant Human Siglec-3/CD33 His-tag (Catalog # 10375-SL) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 44-55 kDa.
Formulation, Preparation and Storage
What does CF mean?
CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our
Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant
protein to be stored at a more dilute concentration.
The carrier free version does not contain BSA.
What formulation is right for me?
In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or
as an ELISA standard.
In contrast, the carrier free protein is recommended for applications, in which the presence of BSA
Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose.
Reconstitute at 500 μg/mL in PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage:
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
3 months, -20 to -70 °C under sterile conditions after reconstitution.
Siglecs (sialic acid binding Ig-like lectins) are I-type (Ig-type) lectins belonging to the Ig superfamily. They are characterized by an N-terminal Ig-like V-type domain which mediates sialic acid binding, followed by varying numbers of Ig-like C2-type domains (1, 2). Eleven human Siglecs have been cloned and characterized. They are sialoadhesin/CD169/Siglec-1, CD22/Siglec-2, CD33/Siglec-3, Myelin-Associated Glycoprotein (MAG/Siglec-4a) and Siglecs 5 to 11 (1-3). To date, no Siglec has been shown to recognized any cell surface ligand other than sialic acids, suggesting that interactions with glycans containing this carbohydrate are important in mediating the biological functions of Siglecs. Siglecs 5 to 11 share a high degree of sequence similarity with CD33/Siglec-3 both in their extracellular and intracellular regions. They are collectively referred to as CD33-related Siglecs. One remarkable feature of the CD33-related Siglecs is their differential expression pattern within the hematopoietic system (1, 2). This fact, together with the presence of two conserved immunoreceptor tyrosine-based inhibition motifs (ITIMs) in their cytoplasma tails, suggests that CD33related Siglecs are involved in the regulation of cellular activation within the immune system. Human Siglec-3 is alternatively known as myeloid cell surface antigen CD33 and GP67. Human Siglec-3 cDNA encodes a 364 amino acid (aa) polypeptide with a hydrophobic signal peptide, an N-terminal Ig-like V-type domain, one Ig-like C2-type domains, a transmembrane region and a cytoplasmic tail (1, 4). Siglec-3 expression is restricted to cells of myelomonocytic lineage (2). It binds sialic acid preferring alpha 2,3-linkage over alpha 2,6-linkage (5). Studies indicated that Siglec-3 recruits SHP-1 and SHP-2 to its ITIMs (6, 7). When co‑cross‑linking with Fc gamma R1, Siglec3- inhibits tyrosine phosphorylation and calcium mobilization, suggesting Siglec-3 can mediate inhibitory signals (7).
Crocker, P.R. and A. Varki (2001) Trends Immunol. 22:337.
Crocker, P.R. and A. Varki (2001) Immunology 103:137.
Angata, T. et al. (2002) J. Biol. Chem. 277:24466.
Simmons, D. and B. Seed (1988) J. Immunol. 141:2797.
Freeman, S.D. et al. (1995) Blood 85:2002.
Taylor, V.C. et al. (1999) J. Biol. Chem. 274:11505.
Ulyanova, T. et al. (1999) Eur. J. Immunol. 29:3440.
Citations for Recombinant Human Siglec-3/CD33 His-tag Protein, CF
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FAQs for Recombinant Human Siglec-3/CD33 His-tag Protein, CF
Is this protein the wild-type or does it contain a mutation at amino acid 69 (R69G)?
The sequence of this protein is Met17-His259, with a C-terminal 6-His tag, and the full referenced sequence for the expressed protein can be found in the Accession section on the product page. This sequence does not contain the R69G natural variant mutation.
Product Documents for Recombinant Human Siglec-3/CD33 His-tag Protein, CF
Which Brands are Currently Available on bio‑techne.com? R&D Systems, Tocris Bioscience and ProteinSimple branded products are available to purchase through bio‑techne.com. ProteinSimple branded instruments are available to quote. ACD branded products will be available on bio‑techne.com in the near future. Novus Biologicals branded products are not currently available on bio‑techne.com and can be found at novusbio.com.
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